First time Boot issue. (troubleshooting)

Greyrender

Prominent
Jul 27, 2017
4
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510
Hi new to computer builds i've made a few for friends & family.
I've followed the guidelines for properly booting a PC and RTFM.
However I can't identify the problem. if this is obvious to anyone then I'd be really happy to have saved the time.
https://youtu.be/FJLE1aelxCU

It seems to short and never finish booting. but it keeps rebooting again.
any advice would be appreciated.
can post build.
used PCpartpicker but forgot to save it. but for what's plugged in
7thGen I3-7100 CPU
Corsair cx 450 PSU
Cryorig C7 Aftermarket Cooler.
stock case fans.
h270 HD3 Gigabyte Mother board
additional information can be provided.
 


I guess that's phrasing it poorly.
but essentially it starts and the components seem to go into action,seize up and resume functioning.
If I plug it in the disk drive will open *when pressed*,then close by itself. guessing that's a result of whatever is happening with the motherboard/psu
 


Thanks RAM didn't work,RMA it is.
Appreciate the time & effort.